1. Field of the Invention
This invention relates to vascular occlusion removal or thrombus dissolution or destruction devices. More specifically, this invention relates to thrombus dissolution devices or catheters for insertion in body vessels for removing obstructions therefrom. Yet more specifically, this invention relates to apparatuses or thrombectomy devices for removing vascular obstructions such as thrombi by the creation of turbulence or a vortex near or adjacent to an obstruction or occlusion. Concurrently or subsequently, suction or aspiration removal of the resulting disintegrated obstruction material is described.
2. Description of the Prior Art
The removal of harmful blockages from vessels, ducts or passages within the body is typically accomplished by one of several techniques. One technique utilizes a treatment catheter equipped with two inflatable balloons. The inflatable balloons are used to seal off a constricted area in a duct or passage such as a blood vessel. An inlet member is provided within the catheter for supplying a suitable solvent, such as a thrombolytic agent or solution of digestive enzymes, to the area delimited by the two balloons. An outlet member is provided for removing the dissolved material from the site of the restriction. In addition, a second supply channel is provided for allowing the blood or other body fluid to bypass the delimited area, thus preventing a complete vascular or coronary obstruction. A second technique, balloon angioplasty, involves deployment of a balloon catheter within the obstructed vessel so that, when the balloon is inflated, the constriction or obstruction material is compressed against the vessel walls.
A problem with the above techniques is that they may cause blood vessel wall damage.
Another more recent technique, known as laser angioplasty, uses laser energy to vaporize an obstruction. In this technique, the catheter, which is mounted for rotation and translation about a filament, has a pair of abutments disposed on its distal end. Also included on the distal end of the catheter is a bladder which, when inflated, causes the abutments to bear against the inner surface of the blood vessel so that the space between the abutments defines a working chamber for delimiting the area around an obstruction. A fiber optic connected to a source of laser energy extends through the catheter, with the distal end of the fiber optic being disposed in one of the abutments. In addition, a suction port is provided between the abutments for removing disintegrated material from the delimited area. Severing means such as a blade or a heated element also may be included for severing and releasing material which is not vaporized by the laser. As with balloon angioplasty, laser angioplasty can result in damage to the blood vessel itself.
Another technique for removal of blockages utilizes what is generally referred to as an atherectomy device or catheter. An example of this type of device is disclosed in U.S. Pat. No. 4,631,052 to Kensey. The Kensey '052 patent device comprises a bladed cutting head which is rotated by a turbine drive to cut away occlusions in a body vessel. This Kensey '052 catheter presents the possibility of vessel wall damage if its rotary head were to be deflected by an especially hard portion of an occlusion.
U.S. Pat. No. 4,950,238 issued to Dennis E. Sullivan describes a hydro-rotary vascular catheter which is a variation on the balloon angioplasty technique described above. Sullivan discloses a catheter having a rotary, fluid-directing head and isolation means, e.g., balloons, which are positioned upstream and downstream of the obstruction. After being positioned, the upstream and downstream balloons are inflated with the patient's blood and a pressurized flushing fluid, respectively, to seal off the obstruction. Flushing fluid is ejected from the rotary fluid-directing head of the Sullivan catheter which causes the head to rotate. This rotation creates turbulence which, in conjunction with the fluid streams themselves, is said to break down the vessel obstruction. A return channel permits debris to be removed from the constricted area. The Sullivan device is structurally complicated and has the admitted drawback of occasionally requiring the use of digestive enzymes or other solvents such as those used in some forms of vascular treatment discussed above.
U.S. Pat. No. 4,749,376, to Kenneth Kensey et al. discloses a "Reciprocating, Working Head Catheter". The catheter of Kensey et al. comprises an elongated drive wire extending through the catheter body and a motion transtator located at the distal end of the catheter. The drive wire is rotated at high speed and the transtator translates the rotary motion into reciprocating motion. In this manner the working head is rotated and reciprocated. This motion, in conjunction with a fluid, permits the catheter to open the body vessel in which it is inserted. No aspiration or removal of debris is disclosed or suggested in the Kensey et al '376 patent.
U.S. Pat. No. 4,445,509 to David C. Auth discloses a rotating head cutting tool recanalization catheter having spirally shaped cutting flutes with hardness-differential cutting properties. Plaque and other obstructions are alleged to be removed from organic structures without damage to normal tissue. The cutting apparatus of the Auth et al. patent is disclosed to be rapidly rotated within the blood vessel of a patient by means of an external torque-generating device, e.g., an electric motor. In operation, then, the cutting tool is advanced against a blood vessel lesion or obstruction and the obstruction is differentially cut. The apparatus of Auth et al. has a fluid port in communication with an external suction device so that blood and debris from the cutting operation can be removed from the cutting site.
U.S. Pat. No. 4,631,052 to Kenneth R. Kensey discloses a rotating head or recanalization catheter which is advanced through the body passageways to the site of a restriction. The apparatus of the Kensey '052 patent is disclosed to operate by cutting or by mechanically beating or otherwise agitating or disturbing the blockage material to form an opening. A perfusion structure is provided which provides oxygenated fluids, drugs, contrast media or dyes into the occluded or blocked passage way.
U.S. Pat. No. 4,795,438 also to Kenneth Kensey discloses a method and apparatus for forming a restriction in a vessel, such as a fallopian tube. No removal of unwanted vascular obstructions is disclosed or contemplated in the Kensey '438 patent.
U.S. Pat. No. 4,784,636 to Mark A. Rydell discloses a balloon atherectomy catheter. The Rydell '636 patent apparatus has an angular cutting tip fixed to the distal end of an elongated drive tube. A separate rotational drive mechanism is coupled to the drive tube to rotate the drive tip. Provision is made for introducing fluid through the loop of the guide catheter for inflating the balloon and for aspirating blood and loose particles away from the occlusion site. The balloon mechanism is used primarily to retain the distal end of the catheter assembly in place near the occlusion to permit the cutting operation to be performed.
U.S. Pat. No. 4,715,538 to Horst Lingnau and U.S. Pat. No. 3,120,326 to Ernie D. Willhoite disclose jet nozzles and rotary spray devices, respectively. The inventions of Lingnau and Willhoite are useful for cleaning narrow tubular parts, such as pipes, or for drilling though soft materials by means of jet or spray nozzles. These references make no mention of possible medical applications of these inventions.
Recently, a catheter has been described which comprises a distal end header in fluid communication with a plurality of proximal end- or backward-directed high pressure jets. Fluids are fed to the header through the body of the catheter by means of an off-center input pipe or lumen. The high pressure jets direct fluid backward away from the thrombus, and thereby create a vortex which allegedly tends to remove it. No rotation of the header is possible.
None of the above patents alone or in combination disclose or suggest the invention of the present application.